TIL: Mongo Sucks

MongoDB $nin and $ne and $exists: false queries are super expensive. I
mean there is a point at which they are basically unusable. And I learned it
the hard way, having developed a service, that relies heavily on this kind of
queries to emulate queue-like workflow. 5+ million documents later and I’m
hurriedly adding indexes for all flags that take more than 60 seconds to query
for.

Information on this issue is limited to a short FAQ entry at Mongo docs and a couple StackOverflow
answers. That’s it. Come on, it should be the first
thing people see, when they open Mongo docs - a huge dialog you should scroll
through three times before you can click accept.